Cardiac rehabilitation, including physical training, has become accepted treatment following myocardial infarction, coronary stent implantation and coronary bypass operation. Besides modifying patients' risk profile for future coronary problems, the focus is on improving exercise capacity. The ability to be able to perform at a higher maximal level is a strong predictor for outcome (new cardiovascular events and mortality). The main purpose of this study is to evaluate whether aerobic interval training outweighs more classical moderate endurance training in improving exercise capacity. During interval training, patients perform exercise at high intensity, but for only a couple of minutes and then recover at a lower intensity. Such intervals are repeated. Preliminary evidence from smaller studies suggests that this type of training leads to a larger increase in exercise capacity, compared to the more traditional endurance training at moderate intensity.